Inpatients from the Chestnut Lodge follow-up study diagnosed with character disorder were studied to predict future schizophrenic decompensation. Individually, three DSM-III criteria for schizotypal personality disorder predicted schizophrenia at long-term follow-up: magical thinking, suspiciousness or paranoid ideation, and social isolation. Additionally, lower IQ, poorer premorbid quality of work, and transient delusional experiences were predictive. No borderline personality disorder criterion was predictive. This suggests that schizotypal but not borderline personality disorder belongs in the schizophrenic spectrum. Within schizotypal personality disorder, criteria from both familial and clinical traditions appear to be dimensions of vulnerability to psychosis.